Yeah stuff like that really ain’t it

Yes it is

It works in a few use cases,

It works in every case where you have multiplying and dividing, including fractions and percentages

but is objectively wrong

No it isn't

detracts from understanding the topic properly

Enhances it actually

That’s why I teach percentages as the fractions they are.

Sounds like you're only teaching as much as you understand. Try understanding more. Students love the tricks that make Maths easier, including this one.